Two-temperature refrigerating apparatus



March 16, 1954 .1.w. JAcoBs TWO-TEMPERATURE REFRIGERATING APPARATUS 4Sheets-Sheet 1 I IIUI .IIHHHIH IIIIIIIIIIVHH,

Filed Nov. 5, 1950 Z0] VENTOR.

March 16, 1954 W JACOBS 2,672,018

TWO-TEMPERATURE REFRIGERATING APPARATUS Filed Nov. 3, 1950 4Sheets-Sheet 2 INVENTOR. 'f// ZU March 16, 1954 J W, JACOBS 2,672,018

TWO-TEMPERATURE REFRIGERATING APPARATUS Filed Nov. 5, 1950 4Sheets-Sheet 5 aso'l March 16, 1954 Filed Nov. 3, 1950 J. w. JAcoBs2,672,018

TWOTEMPERATURE REFRIGERATING APPARATUS 4 Sheets-Sheet 4 #v51/MUM 472 480INVENTOR.

Patented Mar. 16, 1954 UNITED STATES PATENT OFFICE TWD-TEMPERATUREREFRIGERATIN G APPARATUS poration of Delaware Application November 3,1950, Serial No. 193,963

14 Claims.

This invention relates to refrigerating apparatus and more particularlyto household refrigerators in which the food compartment is refrigeratedat temperatures above freezing by the evaporator in a secondary circuitwhich has its condenser thermally connected to a freezing evaporator inheat exchange relationship with a-freezing compartment.

It is an object of my invention to provide a snap action control forsuch a refrigerator which will maintain proper temperatures in the foodcompartment and which will provide a convenient means for defrosting theevaporator of the secondary circuit.

It is another object of my invention to provide a snap acting valve forcontrolling the circulation in the foodcompartment evaporator in suchrefrigerator to make it possible to defrost the food compartmentevaporator.

It is another object of my invention to provide a combination snapacting valve and switch having a common pressure actuating means andconvenient common adjusting means.

It is another object of my invention to provide a snap acting valvehaving a pressure responsive actuating means and the toggle meansdirectly connected to the valve element.

It is another object of my invention to provide a pressure operated snapacting valve in a secondary refrigerant circuit which is set toautomatically open and close in successive cycles during normaloperation of the system.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings:

Fig. 1 is a view partly diagrammatic of a household refrigeratorembodying one form of my invention;

Fig. 2 is a view partly diagrammatic of a household refrigeratorembodying another form of my invention;

Fig. 3 is a sectional view taken along the line 3 3 of Fig. 4 of thevalve in the secondary circuit shown in Fig. 1;

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 3;

Fig. 5 is a sectional view taken along the line 5--5 of Fig. 4;

Fig. 6 is a bottom of the valve shown in Figs. 3 and 4;

Fig. 7 shows a modified form of valve element A,of the valve shown inFigs. 3 and 4;

Fig. 8 is a sectional view of valve shown. in Fig. 2; and

Fig. 9 is a diagrammatic view of a household refrigerator with acombination snap acting switch and valve shown in section.

Referring now to the drawings and more particularly to Fig. 1, there isshown a household refrigerator 20 including a freezing compartment 22and a food compartment 24 each separately enclosed with sheet metalWalls and surrounded by a thermal insulation 2S diagrammaticallyindicated by the dot-and-dash outlines of the cabinet structure. Therefrigeration is accomplished by providing a sealed motor compressorunit 28 which forwards the compressed refrigerant to a condenser fromwhich the liquid is conducted through a supply conduit 32 to anexpansion valve or restrictcr 34 which controls the flow of therefrigerant in this primary 20 refrigerator system into the evaporatingcoils 36 which extend in heat exchange contact with the bottom, top,sides and back of the freezing compartment 22. The refrigerantevaporates in the primary evaporator 3B and is returned through thereturn conduit 38 to the compressor 28.

To insure adequate cooling for the lower part of the compartment, thereis provided a first secondary refrigerant circuit having a condensingportion 40 mounted in heat exchange contact with the back wall of thefreezing compartment 22 so that it is in heat exchange relation with theprimary evaporator 36. A liquid supply conduit 42 extends to the bottomportion of the food compartment 24 and extends around the 35 back andsides to form an evaporating portion 44 which extends upwardly andconnects to a return conduit 46 which discharges into the condensingportion 40.

In the upper portion of the food compartment, there is provided a hollowsheet metal plate 48 located adjacent the rear wall. This plate containsrefrigerant passages and the uppermost refrigerant passage is connectedto the condenser 54 by a return conduit 50 which extends upwardly untilit reaches a point 52 which is above the level of the condenser 54. Thecondenser 54 is in heat exchange contact with the rear wall of thefreezing compartment 22 and it drains through a liquid conduit 56 whichextends to a snap acting valve 58 which may be of the type 55 Referringnow more particularly to Figs. 3 7,

3 there is shown a valve body 52 having the liquid line 56 connected toenter the Valve body directly through the valve seat opening. Theconduit 6U connects directly with the valve and bellows chamber withinthe valve body 62. Shown upon the valve seat in Figs. 3 and 4, is avalve member =64 provided witha cover 66 `of some form of syntheticrubber-like material upon a metal disc 68 which in turn is riveted tothe bottom.

of the bellows 16 and to the bottom of the valve stem 12. The upper endof the valve steml 12 has threaded thereon a metal knob member 14 whichis covered with the rubber boot portion of a sealing diaphragm 16 ofsynthetic rubber which has its heavy peripheral portion clamped insealing engagement of the upper rim of the valve body by a gland 18.

Within the upper portion of the valve body 62, there is provided atoggle spring 80 which is semielliptic iin shape as shown in Fig. andwhich lhas its ends bearing against the inner surfaces of the valve body62. Extending between this valve stem-12 and the toggle spring 86 is atoggle blade 84 having knife edges and its opposite ends which engage``notches provided in the toggle spring llf'andwthe valve stem 12. Asecond toggle blade iisprovidedwith knife edges at its opposite endsengaging notches inthe valve stern 12 and a button'88 which is rotatablymounted upon an adjusting screw 96. To obtain a snap action whichwill'cause the valve 64 -tomove quickly from the fully'closed Ipositionto the fully open position, the=adjusting screw 922i is adjusted toapply a column -loading to the toggle blades d6 and 3S and the spring 80which provides a component in the direction of movement of the valvestem which is greaterthan any spring force in the bellows lil. Asuitable seal 92 of synthetic rubber' is provided forthead-justing screwtu so that it together with `the diaphragm seal .16 will effectivelyyprevent the entrance 4'of external air and moisture to the interior ofthe valve body 62.

If it is desired that this `Valve be manually operated,the secondarycircuit is supplied with refrigerant in an amount which is insufficientto fill .the liquid line v5.6 `and the condenser 54 up to -thehighfpoint `5.2. With that arrangement, the :pressure `within the`secondary circuit will be governed'by the temperature of thefcondenseriid and vvill'not risesuiiciently to act on the bellows 16 to rVopen-the valve. By increasing the amount of refrigerant `in the systemuntil it condenses more ithanenough to ll withY liquid the conduit 56and 4thescondenser 5d up to the high point `52, the pressure inthe sytemwhen the valve 58 is closed willrise-according to the temperature oftheplate 48 until it becomes high enough to act on the bellows withsufficient force to overcome the closingcomponent of force of thetogglemechanisrn upon the stern 12 to collapse the bellows Y10 and movethe valve 64 to the fully open position.

If desired, this same arrangementmay be made -toautomatically open andclose the valve 64 in successive cycles by marking the angularity citheftoggle blades 8d and 86 small so that the differential is reduced.If the primary system is controlled by the switch 90. to maintain theyfreezing'compartment 22 in the neighborhood of 0 F.,

-the vali/e258 will for this purpose be adjusted to close upon thesecondaryvcircuit having its pressure reduced to a certain low pointsuch as a pressure equivalent to about 18 F. and maybe set -s`o that'the valve will open when the temperature within the plate 48 reaches avalue above freezing such'as 3`4`"F. The switch U4 is connected Lic inseries with motor compressor unit 28 and is controlled by a thermostatbulb in heat exchange relation with an intermediate portion of theprimary evaporator 36 as well as the high portion or" the secondarycircuit near the point 52. This makes the switch Sli-sensitive toincreases in temperature in either the freezing compartment 22 or thefood compartment 24.

In Fig. 7, the bellows |10 is operatively connected to the valve 64 by acompression type coil spring |65 which `always keeps the metal upperplate 161 oi the valve member 64 in contact with the rivet l'il at thelower end of a valve stem identical to the valve stem 12 shown in Figs.3 and 4. The valve member |64 is provided with a surface of syntheticrubber in a manner similar to the valve member 64.

In Fig. 2, there is shown a household refrigerator 22E including afreezing compartment 222 and-a food compartment 225. These are enclosedwithin insulation the outlines of which are illustrated by thedot-and-.dash outline 225. The refrigerator is provided with a sealedmotor compressor unit 22S which compresses the refrigerant and forcesthe compressed refrigerant into a condenser 23d wherein the compressedrefrigerant is liquefied and conducted through a supply conduit 232 toan expansion Valve or restrictor which controls the flow of liquidrefrigerant to a high temperature evaporator 2M which extends arounflthe bottom, side and rear walls of the food compartment 22-1. Some ofthe liquid refrigerant is conducted through the supply conduit to asecond valve or restrictor 235 which controls the flow of liquidrefrigerant into the freezing evaporator 236 which extends about thebottom, top, side and rear walls of the freezing compartment 222. Theupper ends of the evaporators 235 and 2M are connected to the snapacting valve 258 which is connected by the return conduit 260 to thesealing motor compressor unit 228.

The operation of the sealed motor compressor unit 228 is controlled by adual thermostat switch 294 preferably of the type shown in the GroomsPatent 2,216,589 having one Athermostat bulb 293 located in the freezingcompartment and the second thermostat bulb 295 located in the foodcompartment 224. By this dual thermostat arrangement, the motorcompressor unit will operate whenever either the freezing compartment orthe food compartment 224 requires refrigeration. The construction of thevalve 258 is shown in Fig. 8. The high pressure, high temperatureevaporator 244 connects directly into the bellows chamber 256 of thevalve. The botto-m of this bellows chamber contains a valve seat 2lwhich is adapted to receive the valve member 264 having a covering ofsynthetic rubber. The valve stem 212 connects the valve member 266 tothe bottom of the bellows 210.

At the upper end of the valve stem 212, there is provided a set oftoggle blades 284 and 286. The outer end of the toggle blade 284 has aknife edge which engages a notch in the semi-elliptic toggle spring 280.The outer end of the blade 286 also has a knife edge which engages anotch in the bottom 268 which is rotatably mounted in the adjustingscrew 290 and the access opening to this screw 290 is sealed by asealing member 292 of synthetic rubber. Within the bellows 210, there isprovided a compression type coil spring 21| which at its lower end restsagainst a spring retainer mounted` upon the closed lower end .of thebellows 210. VlThe upper end of the 'compression type coil spring issupported by an upper spring retainer 213 connected by the pins 215 to atransverse connecting member 211 which is threaded upon the hollowadjusting screw 219.

This hollow adjusting screw 219 is rotatably mounted in the adjustablethreaded bushing 29| which may be used for adjustably locating the screw219. The screw 219 is provided with a convenient adjusting knob 283 foradjusting the tension of the compression spring 21| so as to determinethe pressure required within the bellows chamber to collapse the bellows219 to move the valve 264 to the open position. The adjusting screw 299is adjusted to apply a column load to the toggle links 286 and 284 aswell as to the spring 289 sufficient that the component in the directionof movement of the valve stem 212 will begreater than the force of thespring 2li and the bellows 219. This will insure snap action movementwhich will proceed directly from the fully closed position to the fullyopen position and vice versa. The closing pressure of the valve 264 isdetermined by the location of the adjusting screw 295 which is threadedwithin the interior of the hollow screw 219. The interior of this screw219 is closed by a small screw 281 which may be removed to gain accessto the screw 285 for adjusting the closing pressure. This valvemechanism so far described controls only the flow of refrigerant fromthe high pressure evaporator 244. By making this valve pressureresponsive in this manner, the evaporating pressure and temperaturewithin the evaporator 244 may be accurately controlled.

The opening in the valve seat 261 connects to a lower valve chamber 329having a valve seat 322 provided in a valve cage 324 located in thevalve chamber 329. This valve seat 322 is adapted to be closed by avalve member 326 having a periphery of synthetic rubber adapted toengage the seat 322 and having the center portion of metal which isadapted to be held in contact with the lower end of the valve stemextension 328 by a very light compression type coil spring 336. Thevalve cage 324 and the valve 326 divide the valve chamber 329 into aportion communicating directly with the return conduit 269 and the valve264 and a portion connecting with the high pressure evaporator 236. Thecompression spring 339 is light enough so that it just has sufficientforce to hold the valve member 326 in the closed position when theextension 328 of the valve stem 212 is in the upper position. By virtueof this arrangement, when the pressure in the freezing compartment 236is greater than the return conduit 269, evaporated refrigerant will pushthe valve 326 to the open position in the manner of a check valve. Thiswill allow the motor compressor unit to draw refrigerant from both thehigh pressure, high temperature evaporator 244 and the low temperature,low pressure freezing evaporator 236 when both evaporators requirerefrigeration. However, the valve 326 will prevent the flow ofrefrigerant from either -the high pressure evaporator 244 or the return.Aitellthe pressureand. temperaturev .withinths evaporator have beenreduced sufciently the check valve 326 will prevent any flow ofrefrigerant from the high temperature evaporator 244 into the lowpressure evaporator 236.

The valve 264 will close automatically and the extension 328 will forceopen the valve 326 thereby bringing the low pressure evaporator 236directly in open communication with the return conduit 269 so that themotor compressor unit 228 may continue in operation to lower thepressure and temperature in the freezing compartment evaporator 236until both compartments have their requirements satisfied. This providesa very enicient form of operation.

At the bottom of Fig. 9, there is provided a household refrigerator 429in rear view. This refrigerator includes a freezing compartment 422 anda food compartment 424. These compartments are enclosed in insulationindicated by the dot-and-dash outline 426. A primary refrigeratingsystem is provided including a sealed motor compressor unit 428 whichdischarges compressed refrigerant into the condenser 439 where therefrigerant is condensed and supplied through the supply conduit 432 tothe expansion valve or restrictor 434 which controls the iiow ofrefrigerant to the primary evaporator 436 which extends in contact withthe bottom, top, sides and rear walls of the freezing compartment 422.The liquid refrigerant evaporates in the evaporator 436 and is returnedto the motor compressor unit 42S through the return conduit 438. Thebottom of the food compartment is cooled by a secondary refrigerantcircuit having a condenser portion 1449 in heat exchange relation withthe rear walls of the freezing compartment and having an evaporatingportion 444 in contact with the bottom and the lower portion of thesides and rear wall of the food compartment 424.

A second secondary refrigerant circuit is provided with a condensingportion 454 in heat exchange contact with the rear Wall of the freezingcompartment and an evaporator plate 448 within the food compartment 424.This plate is similar to the plate 48. The upper portion of the plate449 is connected to the uppermost portion of the condenser 454. Thelowermost portion of the condenser 454 is connected by a liquid conduit456 to a valve 458. This valve 459 includes a valve body 462 containinga valve seat 459. On the valve seat 459, there is provided a valvemember 464 formed of a metal disc having a synthetic rubber coveringcovering its lower face and its periphery. A valve cage 465 surroundsthe valve member 464 and is connected directly to the lower end of thevalve stem 412 and the lower end of the bellows 419. Between the top ofthe valve cage and the top of the valve member 464, there is provided alight coil spring 461. This serves to hold the valve 464 in contact withthe seat when the valve is in closed position. This provides a fulliioating mounting thus insuring tight closing of the valve 464 vupon theseat 459, when the valve stem 412 is in the position shown in Fig. 9 anda positive opening.

As in the other modications, the valve stem 412 is provided with toggleblades 484 and 486. The toggle blade 464 is provided with a knife edgeat its outer end which bears against the semi-elliptic spring member 489while the toggle blade 496 has a knife edge at its outer end which isreceived within the notch in the button 488. This button 469 isrotatably mounted in the adjusting screw 499 which is sealed by aninsert 492, 0f. synthetic rubber.- ...This adjusting screw 490 isadjusted to appl-y a column load'gto the toggle blades 86` and #86aswell Aas `the spring 480 suflicient to provide a component of `forcein the direction of movement of the valverstem 412 which is greater thanspring lforce of Athe bellows 410 and the light coil spring It?! asrwell as the switch blade 520. This insures sna-p action opening andclosing of the valve member 4M.

The bellows chamber connects to the suppl-y conduitl 46|] which connectsto the `bottom of the plate 448. This secondary circuit is provided withsufficient refrigerant to `flll with liquid the conduit 45B as well as`the `condenser 454 Aso that the pressure within the circuit -w-ill bevresponsive to the temperature of the plate 448 as explained inconnection with the plate 68 in Fig. 1. Although in the diagrammaticview shown in Fig. 9, .the valve 458 is located above the cabinet 420.This 'location is merely used for convenience fin showing the enlargedsection of thewalve and `in reality the secondary circuit is arranged inAa manner similar to that shown in Fig. 1 and lthe valve 458 is mounteddirectly upon the plate `M8 in the seme way as the valve 58 ismountedupon the plate 48 in Fig. 1.

I have found that this `bellows '41!) andthe toggle mechanism can alsobe used to operate a switch mechanism for controlling the motorcompressor unit. `'I'o do this, I have provided a connecting member 522of electrical insulating material which connects `the valve stem 412directly to the switch blade 525 which khas one end anchored to theterminal '5M and the other end provided with a movable switch contact525.

This movable switch contact 52-3 is adapted -to make engagement with anadjustable contact provided upon the adjacent end ci an Yadjustableterminal 52B which is threaded 4through the switch base 530 ofelectrical insulating material. This switch base 530 is mounted Vuponthe top of the valve body 458. The terminal 524 is connected to thesupply conductor A532 while the terminal 528 is connected by theconductor 534 to the sealed motor compressor unit vM728. A second supplyconductor 535 connects to the sealed unit 428.

The terminals '524 and 528 are enclosed within a .covering 538.The'switch Vbase 530 is provided with an adjusting screw 540, providedwith an adjusting knob 5427, at its outer end. The inner end of thescrew 540 serves as a stop to limit the upward movement of the valvestem 412. This determines the temperature and pressure `witlfiin thesecondary circuit at which the valve '64 will move from open to closedposition and the switch contact 525 will move from closed position toopen position tok stop the operation of the motor compressor unit. Theopening of the lvalve 464 and the closing movement of the switch contact526 is adjusted by the adjusting screw 490. By this system, the plate448 maybe operated at temperatures below freezing but before the motorcompressor unit starts, it will rise above freezing temperatures so thatfrost will be melted from every cycle. The cost of the system `isreduced by use of `a single bellows and a single toggle mechanism tooperate `and control both 'the switch and the valve.

` In accordance with the provisions of Rule 78a, reference is made tocopending application S. N. 153,353 filed April 6, 1950, now Patent No.2,611,275.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other forms 8might be adopted, -aszmay-come `within the scope of the claims whichfollow.

What is claimed is as follows:

1. Refrigerating apparatus including an insulated household refrigeratorcabinet having a freezing compartment and a food compartment, a.refrigerating system including separate evap orating means for`separately cooling each -of said compartments and a li'quefying means,a .snap action valve means connected to and in series with the separateevaporating means for .the food compartment to control `the ow Vofrefrigerant, said valve means including a pressure responsive meansexposed to the pressure within said separate evaporating -means for .the`food compartment and operably connected to .said snap action valvemeans and proportioned for opening said valve means upon the attainmentof a predetermined high pressure corresponding to a temperature abovefreezing and for closing said valve means upon the attainment of `apredetermined low pressure corresponding V.to .a .temperature belowfreezing.

2. Refrigerating apparatus includingan insulated refrigerator cabinethaving'a freezing Acompartment and a food compartment, a refrigeratingsystem including separate -evaporating means for separately cooling eachof said compartments and a liquefying means, a snap action valve meansconnected to and in series with l.the separate evaporating ymeans forthe food compartment to control the ilow of refrigerant, said valvemeans including a pressure responsive .means exposed to the pressurewithin said separate evaporating means for the -food compartment andoperably connected to said snap action `valve means for opening saidvalve means upon the attainment of apredetcrmined highpressure and forclosing said valve means upon the attainment of a predetermined lowpressure, and a switch means controlled by said pressure responsivemeans for controlling the operation of said liquefying means.

`.3. Refrigerating apparatus including Aan insulated refrigeratorcabinet `vhaving Aa freezing compartment and a food ,compartment forstorage above freezing temperatures, a primary refrigerating ,systemincluding a liquefying means `located outside said compartments andaprirnary evaporating means 'located in heat exchange relation with thefreezing compartment, a secondary refrigerant circuit having `acondensing means located in heat exchange relation with said primaryevaporating means and a secondary evaporating means located in heatexchange relation with said `food compartment, and a temperatureresponsive means responsive to tem- Deratures 0f .said secondaryevaporating means for starting and ,stopping the operation .of saidliquefying means.

4.A Refrigerating apparatus including .a primary refrigerating systemcomprising liquefying means and evaporating means, .a rsecondary refrigerant circuit including a .condensing means in heat exchange.relation with the evaporating means `of said primary system and anevaporat ing means, means for shielding the evaporating means 0f the.Drimarysystem from the evaporatving means of the secondary circuit,anda pressure operated snap action valve means connected in saidsecondary circuit "be'tweenfthe .evaporating means and the vcondensingmeans, said snap action valve means having a. completely closed Positionfor stopping circulation in xmseeaneary circuit and an open positionpermitting circulation in this circuit.

5. Refrigerating `apparatus including a primary refrigerating systemcomprising liquefying means and evaporating means, a secondaryrefrigerant circuit including a condensing means in heat exchangerelation with the evaporating means of said primary system and anevaporating means, means for shielding the evaporating means of theprimary system from the evaporating means of the secondary circuit, anda snap action valve means connected in said secondary circuit betweenthe evaporating means and the condensing means, said snap action valvemeans having a completely closed position for stopping circulation inthe secondary circuit and an open position permitting circulation inthis circuit, and a pressure responsive means in said secondary circuitoperably connected to said snap action valve means to move the valvemeans from one position to another upon a predetermined change inpressure.

6. Refrigerating apparatus including a primary refrigerating systemcomprising liquefying means Aand evaporating means, a secondaryrefrigerant circuit including a condensing means in heat exchangerelationA with the evaporating means of said primary system and anevaporating means, means for shielding the evaporating means of theprimary system from the evaporating means of the secondary circuit, saidcondensing means having its inlet above its outlet, a snap action valvemeans connected in said secondary circuit between the outlet of saidcondensing means and the evaporating means of said secondary circuit,said snap action valve means having a completely closed position forstopping the iiow of refrigerant from said condensing means to theevaporating means of said secondary circuit and an open positionpermitting unobstructed liquid ow.

7. Refrigerating apparatus including "a primary refrigerating systemcomprising liquefying means Iand evaporating means, a secondaryrefrigerant circuit including a condensing means in heat exchangerelation with the evaporating means of said primary system and anevaporating means, means for shielding the evaporating means of theprimary system from the evaporating means of the secondary circuit, saidcono densing means having its inlet above its outlet, a snap actionvalve means connected in said secondary circuit between the outlet ofsaid condensing means yand the evaporating means of said secondarycircuit, said snap action valve means having a completely closedposition for stopping the flow of refrigerant from said condensing meansto the evaporating means of said secondary circuit and an open positionpermitting unobstructed liquid iiow, said secondary circuit containingan amount of refrigerant more than sufficient to fill with liquidrefrigerant the portion of said secondary circuit between said valvemeans and the condenser inlet.

8. Refrigerating apparatus including a primary refrigerating systemcomprising liquefying means and evaporating means, a secondaryrefrigerant circuit including a condensing means in heat exchangerelation with the evaporating means of said primary system and anevaporating means, means for shielding the evaporating means of theprimary system from the evaporating means of the secondary circuit, saidcondensing means having its inlet above its outlet, a snap action valvemeans connected in said secondary circuit between the outlet of saidcondensing means and the evaporating means of said secondary circuit,said snap action valve means having a completely closed position forstopping the iiow of refrigerant from said condensing means to theevaporating means of said secondary circuit and an open positionpermitting unobstructed liquid flow, said secondary circuit containingan amount of refrigerant more than sufficient to fill with liquidrefrigerant the portion of said secondary circuit between said valvemeans and the condenser inlet, and a pressure responsive means exposedto the pressure within said secondary circuit and operably connected tosaid valve means to move the valve means from one of said positions toanother upon a predetermined change in pressure.

9. Refrigerating apparatus including an insulated refrigerator cabinethaving a freezing compartment and a food compartment, a refrigeratingsystem including separate evaporating means for separately cooling eachof said compartments and a liquefying means, a snap action valve meansconnected to and in series with the separate evaporating means for thefood compartment to control the flow of refrigerant, said valve meansincluding a pressure responsive means exposed to the pressure withinsaid separate evaporating means for the food compartment and operablyconnected to said snap action valve means for opening said valve meansupon the attainment of a predetermined high pressure and for closingsaid valve means upon the attainment of a predetermined low pressure,said liquefying means being connected to supply to and withdrawrefrigerant from both of said separate evaporating means, a check valveconnected in series with said separate evaporating means for thefreezing compartment, and means responsive to the closing of said snapaction valve means for positively opening said check valve.

10. Refrigerating apparatus including a primary refrigerating systemcomprising liquefying means and evaporating means, a secondaryrefrigerant circuit including a condensing means in heat exchangerelation with the evaporating means of said primary system and anevaporating means, means for shielding the evaporating means of theprimary system from the evaporating means of the secondary circuit, anda snap action valve means connected in said secondary circuit betweenthe evaporating means and the condensing means, said snap action valvemeans having a completely closed position for stopping circulation inthe secondary circuit and an open position permitting circulation inthis circuit, and a pressure responsive means in said secondary circuitoperably connected to said snap action valve means to move the valvemeans from one position to another upon a predetermined change inpressure, said pressure responsive means and the snap action of saidvalve means being proportioned to open said valve means when therefrigerant in said secondary circuit reaches a oressure correspondingto a temperature just above freezing on thesaturated vaporpressure-temperature curve, said pressure responsive means and the snapaction of said valve means being proportioned to close said valve meanswhen the refrigerant in said secondary circuit reaches a pressurecorresponding to a temperature below freezing on the saturated vaporpressure temperature curve.

11. Refrigerating apparatus including an insulated householdrefrigerator cabinet having a freezing compartment and a foodcompartment, a refrigerating system including a freezing evaporator inheat exchange relation with said freezing compartment and a refrigeratedplate evaporator located entirely in said food compartment and anotherevaporator surrounding the outside of a portion of the food compartment,means for thermally shielding the freezing evaporator from the otherevaporators and from the food compartment, and control means for saidrefrigerating system for maintaining said freezing compartment and saidfreezing evaporator below freezing temperatures at all times and forcycling said refrigerated plate evaporator upon a defrosting cycle aboveand below freezing and maintaining said food compartment at temperaturesabove freezing.

12. A snap action valve including a valve body having a valve seat and afluid passage associated with the seat, a valve member adapted to engagethe valve seat to close the fluid passage, a bellows having its open endsealed to the valve body and its closed end connected to said valvemember, and a set of column loaded toggle links having their adjacentends connected to the closed end of the bellows and having their outerends connected to the valve body for providing snap action movement,said valve body having a second valve seat and a second fluid passageassociated with the second valve seat, a second valve member for closingsaid second Valve seat, and a connection between said second valvemember and the closed end of said bellows.

13. Refrigerating apparatus including an insulated householdrefrigerator cabinet having a freezing compartment and a foodcompartment, a refrigerating system including a liquefying means and afreezing evaporating means associated with the freezing compartment anda food compartment evaporating means, said freezing and food compartmentevaporating means being connected in parallel fluid circuit arrangementwith each other, a check valve at the outlet of said freezingevaporating means, a snap acting pressure operated valve at the outletof said food F2 compartmentl e'vapcrating'.l means, and' means operatedby said pressure' operated valve when in closed posiiionfor' positivelyopening said check valve'A whenever `said pressure operated valve isclosed.

1'4". Refrigerating' apparatus including an insulated householdrefrigerator cabinet having a freezing compartment and a foodcompartment, a refrigerating systemy including a freezing evaporator inheat exchange relation with said freezing compartment and a refrigeratedplate evaporator located entirely in said' food compartment and anotherevaporator surrounding the outside of aportion of the food compartment,means for 'thermally shielding the freezing evaporator from the otherevaporators and from the food compartment, and control means for` saidrefrigerating system for maintaining said freezing compartment and saidfreezing evaporator below freezing temperatures at all times and forcycling said' refrigerated plate evaporator upon a defrosting cycleabove and below freezing and maintaining isaid food compartment attemperatures above freezing, said refrigerating system including aprimary refrigerant liquefying means for supplying 'liquid refrigerantto said freezing evaporator, said control means including meansfor-cycling said refrigerant liquefying means.

JAMES W. JACOBS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,036,756 Hull Apr. 7, 1936 2,038,198 Replogl'e Apr. 21, 19362,050,959 Ncrmelli Aug. 11, 1936 2,154,299: Bixler Apr. 11, 19392,181,276 Koge1 Nov. 28, 1939 2,352,798 Miller July 4, 1944 2,449,688Brinkoeter Sept. 21, 1948 2,503,922 Schumacher Apr. 11, 1950 2,580,219Cooper Dec'. 25:, 1951 2,580,220 Cooper Dec. 25, 1951

